Recently, automatic recognition systems, such as bar code systems, have become widespread. FIGS. 1A and 1B show cross sectional views of the structure of a conventional bar code reading device. FIG. 1A shows the device in an idle state. FIG. 1B shows the device reading a bar code.
As shown in FIGS. 1A and 1B, a contact-type bar code reading device 100 includes an optical reading unit 200 for reading a bar code, a signal processing unit 300 for processing information in the bar code read by the optical reading unit 200, and an activation switch 400 for controlling when the bar code reading device 100 is on/off.
The optical reading unit 200 has a light source (not shown) for providing irradiating light to the bar code, an optical system (not shown) for collecting light reflected from the bar code, and a solid-state imaging device (not shown) for detecting the light collected by the optical system.
The operation of the contact-type bar code reading device 100 will now be described. As shown in FIG. 1A, the bar code reading device 100 and the optical reading unit 200 may be idle or turned off when the activation switch 400 is not pushed.
As shown in FIG. 1B, a user pushes the activation switch 400 to read the bar code. When the activation switch 400 is pushed, the bar code reading device 100 becomes operational, and the optical reading unit 200 irradiates light from the light source. For example, the bar code reading device 100 may be activated to read a bar code 510 printed on sheet surface 500. Light reflected from the bar code 510 is detected by the solid-state imaging device of the optical reading unit 200. The detected light is then subjected to analysis by the signal processing unit 300.
In conventional devices, the activation switch 400 is provided on a surface different from a surface of the bar code. Therefore, in order to read the bar code, the user must push the activation switch 400 prior to reading the bar code, or alternatively, after the bar code reading device is brought into contact with the surface 500.
Unfortunately, requiring the user to separately push an activation switch has several disadvantages. The operation time of the bar code reading device is prolonged. Since the solid-state imaging device is activated by the user, peripheral light may enter the bar code reading device and onto the solid-state imaging device, and thus, cause an erroneous determination. In addition, excessive light may cause the solid-state imaging device to become saturated. As a result, the solid-state imaging device may require time to recover and consume more power. Furthermore, the user must coordinate pushing the activation switch with reading the bar code, and thus, the reading the bar code may become difficult to easily coordinate.
Accordingly, it would be desirable to provide methods, apparatus, and systems that overcome these and other shortcomings of conventional bar code devices.